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71.
介绍了采用非接触式电容传感器、电涡流传感器组合系统获取检测信号,利用基于LabVIEW软件平台的计算机实现对塑料薄膜进行在线检测的工作原理,并对该检测系统的硬件设计、软件设计进行了详细地探讨。最后,给出了测试结果,证明了系统的可靠性与可行性。 相似文献
72.
Film condensation is a vital phenomenon in the nuclear engineering applications,such as the gas-steam pressurizer design,and heat removing on containment in the case of postulated accident.Reynolds number in film condensation can be calculated from either the mass relation or the energy relation,but few researches have distinguished the difference between them at present.This paper studies the effect of Reynolds correlation in the natural convection film condensation on the outer tube.The general forms of the heat transfer coefficient correlation of film condensation are developed in different flow regimes.By simultaneously solving a set of the heat transfer coefficient correlations with Remass and Reenergy,the general expressions for Remass and Reenergy and the relation between the corresponding heat transfer coefficients are obtained.In the laminar and wavefree flow regime,Remass and Reenergy are equivalent,while in the laminar and wavy flow regime,Remass is much smaller than Reenergy,and the deviation of the corresponding average heat transfer coefficients is about 30% at the maximum.In the turbulent flow regime,the relation of Remass and Reenergy is greatly influenced by Prandtl number.The relative deviation of their average heat transfer coefficients is the nonlinear function of Reynolds number and Prandtl number.Compared with experimental results,the heat transfer coefficient calculated from Reenergy is more accurate. 相似文献
73.
《Journal of Industrial and Engineering Chemistry》2014,20(5):3234-3242
This paper reports the equilibrium, kinetics and thermodynamic studies of arsenate adsorption onto freshly precipitated iron hydroxide. Adsorption of arsenate onto iron hydroxide depends on arsenate concentration, contact time and temperature. The intrapartical diffusion model indicates that both the film and intrapartical diffusion control arsenate adsorption on iron hydroxide. The values of activation energies (Ea) indicate the chemical nature of adsorption accompanied by diffusion controlled processes as the rate limiting step. The endothermic nature of the adsorption process suggests that adsorption reaction consumes energy. The negative values of ΔS# can be assigned to decreased randomness at the solid liquid interface. 相似文献
74.
75.
Pooja Sarker Sapan Kumar Sen M.N.H. Mia M.F. Pervez A.A. Mortuza Sazzad Hossain M.F. Mortuza M.H. Ali Salahuddin Nur Humayun Kabir M.A.M. Chowdhury 《Ceramics International》2021,47(3):3626-3633
This study reports the influences of gamma irradiation (GI) in the range of 20–100 kGy on CuO thin films via thermal spray pyrolysis technique on the glass substrates. The results demonstrate significant influences of GI on the crystallographic, microstructural and optical characteristics of CuO thin films. The obtained XRD results showed that the crystallinity of the films deteriorates by gradually decreasing crystallite size (from 59.13 to 46 nm) as applied gamma doses increases. However, the basic monoclinic crystal structure remains same. The dislocation density and lattice strain increased with the rise of GI absorbed dose due to the creation of defects. The values of number of crystallites per unit surface area increased as dose increased indicating the abundance of crystallization of nano CuO thin films. A UV–Vis–NIR spectrophotometer was utilized to determine the optical properties and obtained results indicated that the optical energy band gap (OBG) energies reduced from 2.00 to 1.72 eV as the doses increased from 0 to 100 kGy. No distinctions of the monoclinic phase of virgin CuO thin film have been perceived under applied absorbed doses, notwithstanding the slight deterioration of the crystallinity and narrowing the OBG. 相似文献
76.
77.
《Ergonomics》2012,55(11):1621-1629
Abstract The purpose of this study was to investigate the role of the biceps and triceps in rapid elbow extension during the ‘slice’ service in tennis. Six serves, performed by a top male county player (21 years) were studied. Simultaneous cine film (200 Hz) and electromyography (EMG) were used to collect the service data. Impact provided a sonic synchronizing trigger, with biceps and triceps data recorded for a 1 s period before and after the trigger point. Inertia data for the racket were directly determined by a pendulum technique and included in a three segment model of the server's arm. Maximum elbow extension velocities, for the six trials, averaged 44·1, (±3·9) rad7sol;s. Angular velocity values, in the range 24 to 52 rad/s have been reported in tennis and volleyball serving and badminton smashing. Values in excess of 20 rad/s are beyond the contractile velocity range of human skeletal muscle. The contribution of the triceps to rapid forearm extension is therefore questioned. Substantial biceps EMG activity was evident throughout the elbow extension phase, with the peak activity commencing just prior to impact. A powerful stabilizing co-contraction rather than a dominant muscle torque was thus evident at the elbow. Inverse dynamic analysis of the data supported this observation with large resultant internal joint forces, averaging 577 (± 57) N, acting across the elbow joint through impact. The current findings indicate that the triceps activity is more related to elbow stabilization than extension. 相似文献
78.
《低温学》2017
The problem of degraded emissivity of thin films at low temperatures has been a long observed phenomena. Previous efforts at measuring properties have suggested that transmission of energy through the films may play a key role in the thermal performance of multilayer insulation systems at low temperatures. Similarly, recent testing on tank applied systems has suggested a radiative degradation at low temperatures. Two different approaches were used to attempt to measure the transmission of energy through MLI at low temperatures. A laser based measurement system was set up to directly measure transmittance and a calorimetric based measurement system was used to measure relative emittance of a single layer between aluminum foil and double aluminized Mylar. Minimal transmission at long wavelengths were observed through standard MLI blanket materials at deposition thicknesses of even 35 nm. Where transmission was measured, it was too low to effect the performance of a multilayers system. Similarly, the calorimeter showed similar increases of emissivity for both standard blanket materials and aluminum foils. Multiple different methodologies of measurement have all yielded the same result: that there is no transmission through standard MLI blanket materials at wavelengths associated with temperatures as low as 2 K. 相似文献
79.
P-type mixed oxides (CuFeO2 and CuFe2O4) transparent conducting thin films have been successfully deposited on p-type Si (111) substrates at 450 °C by spray pyrolysis deposition (SPD) and annealed at 800 °C for 2 h. The crystal structure, surface morphology and electrical property have been investigated. It is observed that the CuFeO2 and CuFe2O4 thin films as deposited and annealed, have polycrystalline hexagonal structure and the crystallite size increases by annealing processes. The electrical property of the Ni/CuFeO2/Si Metal–Semiconductor–Metal (MSM) photo detectors was investigated using the current–voltage (I–V) measurements. The barrier heights ϕΒ of Ni/CuFeO2/Ni MSM thin films of as deposited and annealed on Si substrates were calculated and its values are 0.478, 0.345 eV, respectively with an applied bias voltage of 3 V. 相似文献
80.
《Organic Electronics》2014,15(7):1695-1701
In this paper, we report the fabrication of small-molecule-based thin-film layers with a thickness of several tens of nanometers on a release layer by bar coating and subsequent stacking onto other organic layers by the developed film transfer method using driving belts and rollers as a prototype roll-to-roll technique. We use novel thermally activated delayed fluorescence (TADF) materials in this process, achieving multilayered organic light-emitting diodes (OLEDs) with high external quantum efficiency (EQE), which is comparable to those of OLEDs prepared by conventional vacuum deposition. The developed film transfer method shows great potential to realize OLEDs with high efficiency at low cost. 相似文献